A google search didn't exposed too much. Some indicate that recreating the spreadsheet from scratch can resolve the issue but that seems like to sledge hammer type approach. Of course if that is the fix, that is what I will need to do but would like to look at other options or understand why this happened.

A gave that a shot. Saved spreadsheet as html. Opened html and saved out as xlsx. Opened xlsx copied over all of the macros and save it out as an xlsm. Install the 2 addins I am using and ran the scripts. Same problem. Script completes as it should with the correct values but when you exit Excel, Excel crashes with the message above.